2009111909185100FALSE20110307135334002011030713555200{17346AE9-09B8-4F63-8551-E2F47DCEFCDD}Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.2.6.1500enSubmarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient delivery to Chesapeake Bay via this pathway. Resource managers are concerned about nutrients that are entering the estuary via submarine groundwater discharge from this primarily agricultural watershed that may be contributing to eutrophication, harmful algal blooms, and fish kills. An interdisciplinary U.S. Geological Survey (USGS) science team conducted field operations in the estuary in April and May 2007. Techniques used included continuous resistivity profiling (CRP), piezometer sampling, seepage meter measurements, and collection of a radon tracer time series. Better understanding of the style, locations, and rates of groundwater discharge could lead to improved models and mitigation strategies for estuarine nutrient over-enrichment in the Corsica River Estuary, and other similar settings. More information on the field work can be accessed from the Woods Hole Coastal and Marine Science Center Field Activity webpage: <http://quashnet.er.usgs.gov/data/2007/07005/> The purpose of this dataset is to provide a seamless elevation/bathymetry grid as a basemap layer for the work in the Corsica River Estuary.VeeAnn A. Cross2011combelevhttps://pubs.usgs.gov/of/2010/1094/data/basemap/elevation.zipraster digital dataVeeAnn A. CrossJohn F. BrattonCharles R. WorleyJohn CrusiusKevin D. Kroeger2011Open-File Report2010-1094Woods Hole Coastal and Marine Science Center, Woods Hole, MAU.S. Geological Survey, Coastal and Marine Geology Programhttps://pubs.usgs.gov/of/2010/1094/Open-File Report2010-1094Woods Hole Coastal and Marine Science Center, Woods Hole, MAU.S. Geological Survey, Coastal and Marine Geology Programhttps://pubs.usgs.gov/of/2010/1094/html/catalog.htmlpublication date2011CompleteNone planned-76.160718-76.06053739.12162239.034459399660.956472408210.9564724321239.9491724330809.949172GeneralU.S. Geological SurveyUSGSCoastal and Marine Geology ProgramCMGPWoods Hole Coastal and Marine Science CenterWHCMSCbathymetryNOAA's Ocean Service, Special Projectshydrographic surveyestuaryestuarine bathymetryelevationdigital elevation modelDEMrasterNational Elevation DatasetNEDLIDARLight Detection And RangingNOAA Coastal Services CenterESRI binary gridNational Oceanic and Atmospheric AdministrationinlandWatersoceansoceans and estuariesoceans and coastalimageryBaseMapsEarthCoverISO 19115 Topic CategoryelevationNorth AmericaNorth AtlanticUnited StatesMarylandCorsica River EstuaryGeneralChesapeake BayNone.The public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey and the National Oceanic and Atmospheric Administration (NOAA) National Ocean Service (NOS) as the originators of the individual datasets. These data are not to be used for navigation. Raster DatasetDepartment of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Special Projects (SP) 1998Silver Spring, MDNOAA's Ocean Service, Special Projects (SP)http://estuarinebathymetry.noaa.gov/raster digital datahttp://ned.usgs.gov/U.S. Geological Survey (USGS), EROS Data Center1999raster digital dataSioux Falls, SDU.S. Geological Surveyhttp://seamless.usgs.gov/http://www.csc.noaa.gov/ldartNOAA Coastal Services Center Coastal Remote Sensing Program20070613raster digital dataTime period of content is 20030301 to 20031130http://www.csc.noaa.gov/lidarVeeAnn A. CrossU.S. Geological SurveyMarine Geologistmailing and physical address

Woods Hole Coastal and Marine Science Center

384 Woods Hole Rd.

Woods HoleMA02543-1598(508) 548-8700 x2251(508) 457-2310vatnipp@usgs.govhttps://pubs.usgs.gov/of/2010/1094/data/basemap/elevation/combelev.gifThumbnail image of the color-coded relief in the Corsica River Estuary area.GIFMicrosoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.2.6.1500combelev399660.956472408210.9564724330809.9491724321239.9491721-76.160718-76.06053739.12162239.0344591enFGDC Content Standards for Digital Geospatial MetadataFGDC-STD-001-1998local timeVeeAnn A. CrossU.S. Geological SurveyMarine Geologistmailing and physical address

Woods Hole Coastal and Marine Science Center

384 Woods Hole Rd.

Woods HoleMA02543-1598(508) 548-8700 x2251(508) 457-2310vatnipp@usgs.gov20110307http://www.esri.com/metadata/esriprof80.htmlESRI Metadata ProfileISO 19115 Geographic Information - MetadataDIS_ESRI1.0datasetfile://\\IGSAGIEGWSVCRX0\D$\edrive\Projects\corsica\forpublication\data\basemap\elevation\combelevLocal Area Network0020.383Raster DatasetDownloadable Data0.383 MB0.383 MBWinZip9.0The WinZip files contains the ESRI binary grid as well as the associated metadata files. https://pubs.usgs.gov/of/2010/1094/html/catalog.htmlhttps://pubs.usgs.gov/of/2010/1094/data/basemap/elevation.zipDVD-ROM4.75GBytesUDFnoneVeeAnn A. CrossU.S. Geological SurveyMarine Geologistmailing and physical address

Woods Hole Coastal and Marine Science Center

384 Woods Hole Rd.

Woods HoleMA02543-1598(508) 548-8700 x2251(508) 457-2310vatnipp@usgs.govNeither the U.S. government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. The data are provided in a WinZip compressed file. The user must have software capable of uncompressing the archive. Additionally, once uncompressed the data are in the ESRI binary grid format. The user must have software capable of displaying this data format. The binary grid is actually made up of two folders, an info folder and the folder with the grid name. Both folders, and their relative path structure are necessary to fully utilize the data.RasterGrid Cell31928530.00000030.000000321Upper LeftFALSEDefault1matrix valuesFALSEGCS_North_American_1983NAD_1983_UTM_Zone_18Nrow and columnmeters30.00000030.000000Universal Transverse Mercator180.999600-75.0000000.000000500000.0000000.000000North American Datum of 1983Geodetic Reference System 806378137.000000298.257222North American Vertical Datum of 1988metersExplicit elevation coordinate included with horizontal coordinates0.1referenced to local tidal datum at the time of the hydrogaphic surveymetersExplicit depth coordinate included with horizontal coordinates0.1NAD_1983_UTM_Zone_18N2128530Meter1 Meter = 1 Meter(s)31930Meter1 Meter = 1 Meter(s)20110307The NED was downloaded in an ESRI binary grid format in a WinZip file. Once extracted, the grid ned_37057094 was created. These original grids are in a geographic coordinate system, NAD83, with a vertical datum of NAVD88. The cell size of these grids is 0.000278 decimal degrees. These files cover the land portion of the area of interest. The cell values where water occurs is usually set to 0 - not true elevation (bathymetry) values. This process step and all subsequent process steps were carried out by the same person - VeeAnn A. Cross.ned_37057094200705VeeAnn A. CrossU.S. Geological SurveyMarine Geologistmailing and physical address

Woods Hole Coastal and Marine Science Center

384 Woods Hole Rd.

Woods HoleMA02543-1598(508) 548-8700 x2251(508) 457-2310vatnipp@usgs.govThe LIDAR was downloaded as a binary floating-point raster dataset. This data file was converted to an ESRI binary grid format using ArcMap 9.1 - ArcToolbox - Conversion Tools - To Raster - Float to Raster. The input dataset was vatnipp17193.flt with the output grid named FloatTo_vatn1. Additionally, the resulting grid needed the projection defined. Based on the metadata, the projection is Geographic, NAD83. This definition was accomplished in ArcMap 9.1 - ArcToolbox - Data Management Tools - Projections and Transformations - Define Projection. The input dataset was FloatTo_vatn1 and the coordinate system chose was GCS_North_American_1983.vatnipp17193.flt200706FloatTo_vatn1The Chesapeake Estuarine bathymetry dataset was downloaded in DEM format. Chesapeake Bay actually required 3 separate DEM's. For the Corsica River Estuary the northernmost of those DEM's covered the area of interest. This file was M130_39076C2_BIG3.dem. The original projection of the data is UTM, Zone 18, NAD27 with a cell size of 30 meters. The vertical datum for the bathymetry is referenced to local tidal datum at the time of the hydrographic surveys that make up the dataset. The vertical unit is meters. The Digital Elevation Model (DEM) estuarine files needed to be converted from the USGS DEM format to ESRI grid format. To do that, ArcMap 9.0 - ArcToolbox - Conversion Tools - To Raster - DEM to Raster. The output data type is float, with the Z-factor left to the default value of 1.200608M130_39076C2_BIG3.dembig3The estuarine bathymetry grids then needed to be projected to UTM, Zone 18, NAD83 - basically just a datum transformation. To do this, ArcMap 9.0 - Data Management Tools - Projections and Transformations - Raster - Project Raster. The geographic transformation used was NAD_1927_to NAD_1980_NADCON. The resampling method was bilinear.big32006big3_nad83The LIDAR grid data was projected from Geographic, NAD83 to UTM, Zone 18, NAD83. This was accomplished with ArcMap 9.2 - ArcToolbox - Data Management Tools - Projections and Transformations - Raster - Project Raster. Parameters as follows: input raster: floatto_vatn1; input coordinate system - GCS_North_American_1983; output raster: csc_utm18; output coordinate system: NAD_1983_UTM_Zone_18N; resampling technique: bilinear. Remainder of the parameters were left to the default. No transformation was necessary.floatto_vatn1200911csc_utm18The NED elevation dataset was projected from the geographic, NAD83 to UTM, Zone 18, NAD83. This was accomplished from ArcInfo command line of ArcGIS 9.1. The command line used to do this was: >NED_UTM18 = project(ned_37057094, geog2utm, bilinear). Effectively what this does is project ned_37057094 using the parameters supplied in the file geog2utm using a bilinear interpolation method. The contents of geog2utm are as follows: >INPUT >PROJECTION GEOGRAPHIC >UNITS DD >DATUM NAD83 >PARAMETERS >OUTPUT >PROJECTION UTM >UNITS METERS >ZONE 18 >DATUM NAD83 >PARAMETERS ENDned_37057094200705NED_UTM18big3_nad83csc_utm18With all the individual datasets in ESRI binary grid format, projection UTM, NAD83, I want to combine the datasets. I do this using raster calculator in ArcMap 9.2 using the following command: merge([big3_nad83], [csc_utm18], [ned_utm18]) Using raster calculator and the merge command, the order of the grids listed is important. The first grid listed has highest priority and will overwrite any values in the same location from the other grids. The second grid listed will overwrite any values in the same location of any grid that comes after it in the list. So in this case, the estuarine bathymetry dataset was assigned priority 1, the LIDAR data priority 2, and to fill in any remaining gaps, the NED data were used. This creates a temporary raster dataset. Then within the table of contents in ArcMap, I right mouse click and select Data - Make Permanent. The resulting output grid is combelev.ned_utm18200911combelevhttp://ned.usgs.gov/U.S. Geological Survey (USGS), EROS Data Center1999raster digital dataSioux Falls, SDU.S. Geological Surveyhttp://seamless.usgs.gov/online1999publication dateNEDThis dataset provided the bulk of the on land elevation data.http://www.csc.noaa.gov/ldartNOAA Coastal Services Center Coastal Remote Sensing Program20070613raster digital datahttp://www.csc.noaa.gov/lidaronline2003030120031130ground conditionLIDARThe LIDAR data provided the higher resolution land data and helped bridge the small gap between the NED elevation data and the bathymetry data.Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), Special Projects (SP) 1998raster digital dataSilver Spring, MDNOAA's Ocean Service, Special Projects (SP)http://estuarinebathymetry.noaa.gov/online18591993ground conditionbathyThis dataset provided all the bathymetric data in the study area.This grid is a combination of three different datasets with three different horizontal accuracies. For the LIDAR data, the metadata reports the horizontal accuracy as "The horizontal coordinate values were designed to meet NSSDA accuracy for data at 1:2400 scale." The metadata for the NED elevation data does not specify a horizontal accuracy. The Chesapeake Estuarine bathymetry dataset metadata reports the horizontal accuracy as "The horizontal accuracy of the DEM is expressed as an estimated root mean square error (RMSE). The estimate of the RMSE is based upon horizontal accuracy tests of the source soundings used to generate the DEM. As a first approximation the locational accuracy of the source soundings are 0.0015 m at source "Smooth Sheet" scale (120 m @ 1:80,000 to 15 m @ 1:10,000). Smooth Sheets are maps generated as a principle product of each (historic) hydrographic survey with fully corrected soundings plotted on them. Digital elevation models comply with the National Map Accuracy Standards (NMAS) accuracy requirements. The positional accuracy is estimated at 3 meters."This grid is a combination of three different datasets with three different vertical accuracies. For the LIDAR data, the metadata reports the vertical accuracy as "The RMSE value of 14.3 cm at the 95% confidence level was determined by an independent accuracy assessment conducted by Dewberry LLC according to the contract specifications. These specifications followed FEMA Appendix A guidelines regarding assessing vertical accuracy. For data accurate to within 18.5 cm RMSE, the guidelines recommended a minimum of 20 independent check points be located in each of 5 different land cover categories: Grass/Ground, High Grass/Crops, Brush/Low Trees, Forest, and Urban/Pavement. A total of 125 points were used for the assessments. These points were surveyed by a licensed land surveyor and provided a positional location and elevation with an accuracy that exceeded the predicted accuracy of the LIDAR data. The entire accuracy reports can be found at <http://dnrweb.dnr.state.md.us/gis/data/lidar>. The RMSE value is 14.3 cm. See the Vertical Positional Accuracy Report section for more information." The metadata for the NED elevation data does not specify a vertical accuracy. The Chesapeake Estuarine bathymetry dataset metadata reports the vertical accuracy as "The vertical RMSE statistic is used to describe the vertical accuracy of a DEM. It encompasses both random and systematic errors introduced during production of the data. The RMSE is encoded in element number 5 of record C of the DEM. This accuracy estimate includes components related to quantization of the source soundings (1.3 to 0.15 m), the systematic editing of the source data (1percentor 0.10m), un-sampled bathymetric features (estimated at less than 5percentof depth), time related changes (erosion, deposition, and seismic shifts), and dredging operations (cut and fill). It is estimated that the accuracy of the Bathymetric DEMs is 2 percent of depth or 1 meter for depths grater than 20 meters and 2 percent of depth or 0.20 meters for depths shallower than 20 meters. THESE DEMs SHOULD NOT BE USED FOR NAVIGATION. There are three types of DEM vertical errors: blunder, systematic, and random. These errors are reduced in magnitude by editing but cannot be completely eliminated. Blunders are errors of major proportions and are easily identified and removed during interactive editing. Systematic errors follow some fixed pattern and are introduced by data collection procedures and systems. Systematic error artifacts include vertical unsampled elevation shifts, relative spacing of the source soundings, misinterpretation of terrain surface caused by softness or poor reflectivity and by the resolution of the collected soundings (feet, feet and fractions, fathoms, fathoms and fractions, meters, tenths of meters etc.). Random errors result from unknown or accidental causes. The 1 degree (DSQ) DEMs are generated from 30 m grids on UTM projection. The RMSE difference between these surfaces is an estimate of the vertical accuracy of the DSQ DEMs."The focus of this dataset is the bathymetry, so that dataset was given priority when combining the datasets. The individual datasets were not checked for errors prior to combining the datasets. Both land elevation datasets (NED and the LIDAR) use the same vertical datum - NAVD88. The bathymetry dataset metadata specified the vertical coordinate system as being referenced to the local tidal datum at the time of the hydrographic survey. These surveys ranged from 1859 to 1993 in the Chesapeake Bay area. No attempt was made to adjust between the two vertical datums represented by these 3 datasets.By combining the three individual datasets, a complete elevation surface for the study area was derived.